Telephone



(No Model.)

J G. H. 'STUT.

TELEPHONE.

Patented May 6, 1890.

' connecting-wires.

UNITED STATES JOHN OH. HENRY STIIT, OF SAN FRANCISCO, CALIFORNIA.

. TELEPHONE.

SPECIFICATION forming part of Letters Patent No. 427,204, dated May 6, 1890.

Application filed November 5, 1887. Renewed September 27, 1889. Serial No. 325,246. (No model.)

To 00% whom it may concern;

Be it known that'I, JOHN OH. HENRY STU'r, of the city and county of San Francisco, State of California, have invented an Improvement in Telephones; and I hereby declare the following to be a full, clear, and exact description of the same.

My invention relates to certain improvements in telephones.

The object is to make the instrument small and inexpensive, producing a large volume of sound and greater variations in the undulations of both the primary and secondary currents, so that conversation may be carried on over greater distance, and inductions, leaks, and resistances better overcome.

It consists in the employment of a confined body of air, oxygen, or other. gas which combines with the carbon when a current of electricity passes between the contacts, thereby increasing the temperature and decreasing the resistance between the contact-points as the vibrations increase the pressure, and decreasing the temperature and increasing the resistance as the pressure decreases. This is efiected by the employment of an air-tight case, within which the operative mechanism of the telephone is contained, and in which the diaphragm forms a portion of one side. Within this case is .contained air or oxygen under pressure, so that a larger number of atoms of oxygen per unit of area are interposed between the contacts. The variation of resistance to the electric current takes place in unison and harmony with the soundwaves striking the diaphragm, the soundwaves being thus transformed into heat-waves of varying temperature by the agency of the electric current between the contacts.

The invention further consists in certain details of construction, all of which Will be more fully explained by reference to the ac companying drawings, in which Figure l is a longitudinal section taken through the case, diaphragm, and interior mechanism. Fig. 2 is a half-plan and halfhorizontal section showing a diaphragm and Fig. 3 is a view of the hinged bar in the rear of the carbon-cup.

In my former patent, No. 355,952, issued to me January 11, 1887, I have shown a carboncup supported by an insulated elastic arm.

with it, so as to prevent any breaking of the circuit when violent vibration of the diaphragm is produced by loud sounds.

This mechanism is contained within an airtight case, into which is introduced air or oxygen under pressure, the effect of which is to interpose more atoms of the gas between the contacts, so that there are more of these molecules per unit of area to combine with the carbon. This brings about a varying temperature between the contacts when set in vibration by the diaphragm, and as the resistance of the carbon to the electric current decreases when the temperature of the carbon increases the sound-waves-are converted into heat-Waves of varying temperature, the effect of which is to vary the temperature and resistance of the carbon,and more especially in the presence of compressed air or oxygen.

A is an exterior case, having a cap or cover B, secured to one side by screws, and a rubber or other packing 0 between it and the main case, so as to make a perfectly air-tight oint.

D is the diaphragm, the edges of which are secured in the rubber or other packing E, so as to form a perfectly-tight joint and also reduce the metallic tones of the diaphragm when set in vibration. To the center of the diaphragm is fixed a piece of carbon F. This carbon has a metallic socket with a nut on one end to hold a plate for the positive conducting-wire to connect with. This wire is insulated where it passes through the case to make connection with the outer positive circuit, while the negative wire connects with the cup and other contact-point by means of a wire a, which passes over the insulated swingmg arm and conveys the current between the cap and the negative conducting-wire. The

carbon piece F extends a short distance inwardly from the dlaphragm, and has its inner end made concave, as shown.

bis the mouth-piece or speaking-tube of the instrument.

G is a concave carbon cap, which is supported by or attached to the cap J so as to stand exactly opposite the concavity of the carbon piece F, and within the cap G is contained a ball of carbon H, which forms the contact between the carbon piece F and the cap G. The cap G has its base connected with a platinum-plated disk I within the shallow cylindrical cup J, and this cup contains granulated carbon, as shown at K, which is insulated from the sides of the exterior cup J by any suitable insulating material, as shown. Upon the opposite side or back of this granulated carbon is a platinum-plated plate or diskL, and a yoke M extends across the back of the cup J and has an adjusting-screw N passing through it and pressing upon the plate or disk L, so that the compression of the granulated carbon within the cup maybe regulated at will, as described in my former patent. The cup J is supported by an arm 0, formed of rubber or non-metallic material, and this arm is hinged or pivoted, as shown at P, so that it may swing freely about the pivot-pins. The cup is suspended upon these pivot-pins by the arm 0, hanging at an angle from its point of suspension, so as to retain the carbons in contact by gravitation. It is allowed to swing about them, and is moved by the vibrations of the diaphragm caused by the action of the sound-waves.

In order to retain the cap G in proper re lation with the carbon F upon the diaphragm and the intermediate ball H, I employ a light spring Q, which is insulated and presses upon the yoke M or other convenient part of the cup J with a light pressure, but which is entirely independent of the insulated arm 0. The effect of this device is to prevent the entire breakage or interruption of the circuit by violent vibrations caused by loud tones. The eifect of these loud tones or the speaker being very close to the diaphragm would cause it to break the circuit entirely, and by using the rigid suspendingarm swinging around the pivots or axis and employing the spring which presses upon the cup the action of the two will serve to prevent the breaking of the circuit. This action is facilitated by the carbon ball, which always rests upon the inside of the cap G, and maintains a perfect contact, notwithstanding the vibrations. In illustration, suppose a sound-wave strikes the diaphragm. The cup J and the cap Gwill have a tendency, first, to oppose the motion; but after acquiring momentum it will be carried so far that the circuit would be broken, except for the action of the spring, which presses upon the back ofthe cup, but not being connected with it will oppose the tendency to e11- tirely break the circuit, because it has less weight and acts quicker. This combination of gravitation and spring action makes a differential action which is not like that of either the spring or gravitation alone. The

chloride of calcium may be employed to entirely deprive the air or gas of moisture. The air within the case escapes through a hole controlled by a screw or valve X when the gas is admitted. By means of this gas under pressure I greatly improve the strength and quality of the tone, because the compression of the air or oxygen introduces a great many more atoms of the gas per unit of area between the contacts of the carbons than when no compression takes place. The advantage of this becomes apparent in connection with the well-known fact that the resistance of carbon to an electrical current is decreased as the temperature of the carbon increases, and this increase of temperature is better effected in the presence of the compressed air or gas. By the rapid vibrations the soundwaves are converted into heat-waves, which thus act to vary the temperature of the car bon, as before described. By rarefying the air or gases the volume of sound becomes less, thus showing the correctness of the above assumption and discovery.

By this construction I am enabled to make the comparatively small and inexpensive telephone produce a large volume of sound and greater variations in the undulations of both primary and secondary currents with a single battery-cell than has heretofore been efiected.

I do not broadly claim in this application the hinged swinging'arm which supports the cap and one of the contact-points, nor the independent spring which produces the differential pressure, as these elements form the subj cot-matter of another application filed by me September 16, 1889, Serial No. 324,07 3.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. In a telephone, a closed case having a diaphragm and mouth-piece set in one side or connected therewith, and the contact-points and operative mechanism contained within the case, in combination with the air or oxygen gas under pressure contained Within said case and acting upon one side of the diaphragm, substantially as herein described.

2. The combination of a closed case containing air or oxygen under pressure, a diaphragm having its periphery fixed in the elastic or other packing at one side of the closed case, the carbon piece fixed centrally to the diaphragm, a carbon cap G, supported upon the pivoted arm, and the ball of carbon H, contained Within the cap and forming the contact between it and the diaphragm-carbon, substantially as herein described.

3. The closed case containing air or oxygen gas under pressure, the diaphragm fixed in the side of the case having the carbon piece attached to its center, the opposing cap and the interposed ball of carbon, and the insulated pivoted pendent arm, by which the cap is supported and about which it moves, in combination with the independent adjustable spring acting upon the back of the cup, substantially as and for the purpose herein described.

4. In a telephone, an air-tight case having a diaphragm fixedto or connected With one side, and a speaking-tube or mouth-piece, the carbon cap and interposed ball through which the circuit is completed, the pivoted suspending-arm, and the independent adjustable spring pressing upon the back of the cup, as shown, said case containing a body of air or oxygen gas under pressure and surrounding the carbon contact-points, substantially as and for the purpose herein described.

5. In a telephone, the closed case having a diaphragm set in one side or connected there- With, and the contact-points contained Within the case, in combination with air or a denser gas under pressure contained Within said case and acting upon one side of the diaphragm, substantially as described.

In Witness whereof I have hereunto set my hand.

JOHN CH. HENRY STUT.

Witnesses:

GEO. H. STRONG, S. H. NoURsE. 

